Biomass Boiler System

ABSTRACT

A biomass boiler system for significantly reducing corrosion and creosote buildup within the interior of a fire container. The biomass boiler system generally includes a primary combustion chamber having an exterior surface and an interior surface, and a water jacket having an inner wall, an outer wall and a water cavity defined between the inner wall and the outer wall. The inner wall is distally spaced from the exterior surface of the primary combustion chamber forming an air chamber. The water cavity contains a volume of liquid heated by thermal conduction of heat from the primary combustion chamber through the air chamber then through the inner wall of the water jacket. The heated liquid may be used for heating, electrical energy generation or other purpose.

CROSS REFERENCE TO RELATED APPLICATIONS

Not applicable to this application.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable to this application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to biomass boilers and more specifically it relates to a biomass boiler system for significantly reducing corrosion and creosote buildup within the interior of a fire container.

2. Description of the Related Art

Any discussion of the related art throughout the specification should in no way be considered as an admission that such related art is widely known or forms part of common general knowledge in the field.

Conventional biomass boilers are used to heat water for usage in heating of a building structure, electrical power generation and the like. Conventional biomass boilers are comprised of a primary combustion chamber (a.k.a. firebox, fire barrel) surrounded by a water chamber. The water within the water chamber is in direct physical contact with the outside surface of the primary combustion chamber to transfer the heat from the primary combustion chamber to the water in the water chamber. The combustion chamber burns the biomass material (e.g. wood, wood pellets, etc.) resulting in heat and smoke being generated within the interior of the primary combustion chamber. The heat from the combustion chamber increases the temperature of the water in the water chamber which is used to heat a building or to produce electricity.

One problem with conventional biomass boilers is that the interior surface of the primary combustion chamber incurs corrosion and creosote buildup because of the direct contact of the water surrounding the primary combustion chamber. The water surrounding the primary combustion chamber, particularly during the initial startup of the biomass boiler, cools the interior surface of the primary combustion chamber so that water vapor from the biomass material is condensed on the interior surface of the primary combustion chamber. Another problem with conventional biomass boilers is that creosote coats the interior surface of the primary combustion chamber when the interior surface temperature of the primary combustion chamber is below 250 degrees Fahrenheit causing the gases from the biomass to liquefy, combine and solidify on the interior surface. Creosote buildup over time reduces the efficiency of the heat transfer from the primary combustion chamber to the water in the water chamber.

Some biomass boilers coat the inside of the primary combustion chamber with ceramic because of ceramics low thermal conductivity to help retain the temperature of the interior surface primary combustion chamber above 250 degrees Fahrenheit. However, ceramic coatings can become damaged over time and reduce the overall efficiency of the biomass boiler by reducing the transfer of heat. In addition, creosote can get behind the ceramic layer on the inside of the primary combustion chamber which cannot be easily cleaned resulting in corrosion and damage to the primary combustion chamber.

Over time, the corrosion and/or the creosote buildup can damage the primary combustion chamber requiring replacement of the biomass boiler. Another problem with conventional biomass boilers is the primary combustion chamber is not removable or replaceable requiring the end user to purchase a new biomass boiler when the primary combustion chamber is damaged.

Because of the inherent problems with the related art, there is a need for a new and improved biomass boiler system for significantly reducing corrosion and creosote buildup within the interior of a fire container.

BRIEF SUMMARY OF THE INVENTION

The invention generally relates to a biomass boiler system which includes a primary combustion chamber having an exterior surface and an interior surface, and a water jacket having an inner wall, an outer wall and a water cavity defined between the inner wall and the outer wall. The inner wall is distally spaced from the exterior surface of the primary combustion chamber forming an air chamber. The water cavity contains a volume of liquid heated by thermal conduction of heat from the primary combustion chamber through the air chamber then through the inner wall of the water jacket. The heated liquid may be used for heating, electrical energy generation or other purpose.

There has thus been outlined, rather broadly, some of the features of the invention in order that the detailed description thereof may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter and that will form the subject matter of the claims appended hereto. In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction or to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of the description and should not be regarded as limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

Various other objects, features and attendant advantages of the present invention will become fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein:

FIG. 1 is a front upper perspective view of the present invention.

FIG. 2 is a cross sectional view taken along line 2-2 of FIG. 1.

FIG. 3 is a cross sectional view taken along line 3-3 of FIG. 1.

FIG. 4 is an exploded rear upper perspective view of the present invention.

FIG. 5 is an exploded front upper perspective view of the present invention.

FIG. 6 is a front view of the present invention.

FIG. 7 is a rear view of the present invention.

FIG. 8 is a top view of the present invention.

FIG. 9 is a bottom view of the present invention.

DETAILED DESCRIPTION OF THE INVENTION A. Overview.

Turning now descriptively to the drawings, in which similar reference characters denote similar elements throughout the several views, FIGS. 1 through 9 illustrate a biomass boiler system 10, which comprises a primary combustion chamber 30 having an exterior surface 32 and an interior surface 34, and a water jacket 20 having an inner wall 18, an outer wall 17 and a water cavity 19 defined between the inner wall 18 and the outer wall 17. The inner wall 18 is distally spaced from the exterior surface 32 of the primary combustion chamber 30 forming an air chamber 40.

The water cavity 19 contains a volume of liquid heated by thermal conduction of heat from the primary combustion chamber 30 through the air chamber 40 then through the inner wall 18 of the water jacket 20. The exterior portion of the water jacket 20 remains at a relatively low temperature (e.g. 190 degrees Fahrenheit or less) to prevent damaging any insulation 25 surrounding the water jacket 20. The interior of the primary combustion chamber 30 is preferably between 700 to 800 degrees Fahrenheit during operation to prevent condensation of water vapor on the interior surface 34 which cause corrosion of the primary combustion chamber 30 and to prevent the accumulation of creosote on the interior surface 34 of the primary combustion chamber 30.

The heated liquid may be used for heating, electrical energy generation or other purpose. The primary combustion chamber 30 is preferably interchangeable to allow for replacement of a damaged primary combustion chamber 30 without having to replace the water jacket 20 or other components of the boiler.

B. Primary Combustion Chamber.

The primary combustion chamber 30 has an exterior surface 32 and an interior surface 34. The primary combustion chamber 30 is constructed of metal or other material capable of withstanding relatively high temperatures (e.g. 700-800 degrees Fahrenheit). The primary combustion chamber 30 may be comprised of various sizes, volumes, shapes and configurations. The primary combustion chamber 30 is smaller in size than the water jacket 20 to be removably received within the water jacket 20 for replacement and/or repair. The primary combustion chamber 30 preferably has a similar shaped structure as the inner wall 18 of the water jacket 20 to provide uniform heat distribution to the liquid within the water jacket 20.

The primary combustion chamber 30 preferably does not have a ceramic coating or other type of insulating layer. In particular, the primary combustion chamber 30 preferably does not have an insulating coating attached to the exterior surface 32 or the interior surface 34 of the primary combustion chamber 30.

The primary combustion chamber 30 is preferably comprised of a main wall 35 forming the exterior surface 32 and the interior surface 34, a front wall 36 connected to the main wall 35 and a second wall connected to the main wall 35 opposite of the front wall 36 as illustrated in FIGS. 2 through 5 of the drawings. The main wall 35 preferably has a circular cross sectional shape forming a cylinder, however, various other cross sectional shapes (e.g. square, rectangular, oval, triangular) may be used for the main wall 35. The main wall 35 is positioned between the opposing end walls 36, 38 and preferably extends orthogonally with respect to the end walls 36, 38.

The primary combustion chamber 30 includes a plurality of air inlet ports 31 within a lower portion of the main wall 35 as illustrated in FIG. 2 of the drawings. The plurality of air inlet ports 31 draw in heated air from the air chamber 40 into the primary combustion chamber 30 for combusting with the gases produced by the biomass material.

The interior surface 34 defines the combustion chamber for combusting a volume of biomass material. The combustion chamber of the primary combustion chamber 30 receives a volume of biomass material for burning such as, but not limited to, wood and wood pellets. Various other types of biomass material may be burned in the primary combustion chamber 30. The biomass material may be added to the primary combustion chamber 30 manually or by an automated conveyor system.

C. Water Jacket.

The water jacket 20 surrounds the primary combustion chamber 30. The water jacket 20 is formed to thermally conduct heat from the primary combustion chamber 30 and is preferably distally spaced a sufficient distance to prevent cooling of the temperature within the primary combustion chamber 30 below 250 degrees Fahrenheit.

The water jacket 20 has an inner wall 18 and an outer wall 17 as best illustrated in FIGS. 2 and 3 of the drawings. The inner wall 18 preferably has a similar shape and size as the outer wall 17, however, the inner wall 18 may have a different shape and/or size compared to the outer wall 17.

At least a substantial portion of the inner wall 18 is distally spaced a distance from the exterior surface 32 of the primary combustion chamber 30 forming an air chamber 40 between thereof. The inner wall 18 of the water jacket 20 preferably has a shape similar to the shape of the main wall 35 of the primary combustion chamber 30 and the inner wall 18 is further preferably distally spaced a distance away from the exterior surface 32 of main wall 35. It is preferable that the distance between the inner wall 18 of the water jacket 20 and the exterior surface 32 of the main wall 35 is consistent, however, varying distances may be used to form the air chamber 40.

A water cavity 19 is defined between the inner wall 18 and the outer wall 17 that contains a volume of liquid to be heated by thermal conduction of heat from the primary combustion chamber 30 through the air chamber 40 then through the inner wall 18 of the water jacket 20. The liquid within the water cavity 19 is preferably comprised of at least water, however, various other liquids may be used within the water cavity 19.

The water jacket 20 is preferably comprised of a cylinder similar in shape to the primary combustion chamber 30 as illustrated in FIGS. 2 through 5 of the drawings. The water jacket 20 has a front opening 24 at a front end portion 22 and a rear opening 28 at a rear end portion 26 of the water jacket 20. The front opening 24 and the rear opening 28 are preferably substantially similar in size and shape.

The water jacket 20 has a water inlet 21 to receive cooled water and a water outlet 29 for dispensing the heated water which is well known in the boiler industry. The end portions 22, 26 of the water jacket 20 are preferably sealed to prevent the water from leaving the water jacket 20 as illustrated in FIGS. 2 through 5 of the drawings. The end portions 22, 26 of the water jacket 20 include extended bracket portions with apertures to receive fasteners to removably secure the rear end plate 27 and the front end plate 23. The front end plate 23 and the rear end plate 27 preferably include insulation 25 that is distally spaced away from the exterior surface 32 of the primary combustion chamber 30 as best illustrated in FIG. 2 of the drawings. To remove the primary combustion chamber 30 from the water jacket 20, the user only has to remove the front end plate 23 thereby allowing removal of the primary combustion chamber 30 through the front opening 24.

A door 54 is used for selectively opening and closing an opening that extends through the water jacket 20 and the primary combustion chamber 30. The user is able to insert biomass material for combustion through the opening when the door 54 is open. An inner throat 50 is attached between the front end plate 23 and the primary combustion chamber 30 as illustrated in FIGS. 2 through 5 of the drawings. The inner throat 50 is secured with conventional fasteners to the primary combustion chamber 30 and the front end plate 23 to allow for removal. An outer throat 52 is attached to the front end plate 23 opposite of the inner throat 50 and the door 54 is removably attached to the outer throat 52. The door 54 may be removably attached in a pivotal manner or completely removable manner to expose the opening that extends through the front end plate 23 and the front wall 36 of the primary combustion chamber 30.

D. Air Chamber.

The air chamber 40 surrounds a substantial portion of the primary combustion chamber 30. In particular, the air chamber 40 preferably completely surrounds the main wall 35 as illustrated in FIGS. 2 and 3 of the drawings. The air chamber 40 preferably surrounds a substantial portion of the front wall 36 and/or the rear wall 38 as illustrated in FIG. 2 of the drawings.

The air chamber 40 preferably has a consistent thickness surrounding the main wall 35 of the primary combustion chamber 30, but may have a varying thickness. The inner wall 18 of the water jacket 20 is preferably not directly connected to the primary combustion chamber 30 as illustrated in FIGS. 2 and 3 of the drawings. The water jacket 20 preferably does not physically contact the main wall 35 of the primary combustion chamber 30 to prevent direct thermal conduction between the water jacket 20 and the main wall 35. The distance between the inner surface of the inner wall 18 of the water jacket 20 and the exterior surface 32 of the primary combustion chamber 30 is preferably approximately one inch or greater than one inch.

An air intake 42 fluidly extends through the rear end plate 27 of the water jacket 20 to provide air from the outside of the boiler into the air chamber 40. The air is heated within the air chamber 40 which in turn heats the inner wall 18 of the water jacket 20 which then heats the water in the water jacket 20. A portion of the heated air enters the combustion chamber of the primary combustion chamber 30 through one or more air inlet ports 31 within the lower portion of the primary combustion chamber 30 as illustrated in FIG. 2 of the drawings. The gases related from combustion are then released from the primary combustion chamber 30 via an exhaust port 74 into the surrounding atmosphere or into a second combustion chamber 70 for a secondary combustion.

E. Secondary Combustion Chamber.

The second combustion chamber 70 fluidly connected to the primary combustion chamber 30 via a connecting tube 60 (a.k.a. smoke/heat tube) as illustrated in FIG. 2 of the drawings. A catalytic unit 62 is connected to the connecting tube 60 to increase the temperature of the secondary combustion in the second combustion chamber 70. The catalytic unit 62 may be comprised of a catalytic combustor or secondary air inserted into the heated gases via at least one secondary air inlets 63. The secondary combustion of the heated gases from the primary combustion chamber 30 increase the overall efficiency of the boiler, reducing creosote production and air pollution. A secondary boiler 80, preferably vertically orientated, receives the secondary gases from the secondary combustion within the second combustion chamber 70 and thermally conducts a portion of the heat therefrom. The exhaust gases are then allowed to be exhausted to the atmosphere via the exhaust port 74. An ash collection unit 72 with a removable collection tray is positioned within a lower portion of the second combustion chamber 70 to collect particles from the secondary combustion.

F. Operation of Preferred Embodiment.

In use, the user inserts a volume of biomass material to be burned within the primary combustion chamber 30. The biomass material is burned at a temperature between 700-800 degrees Fahrenheit. The heat produced within the primary combustion chamber 30 is thermally conducted by the main wall 35, the front wall 36 and the rear wall 38 of the primary combustion chamber 30. The air within the air chamber 40 thermally conducts the heat from the main wall 35, the front wall 36 and the rear wall 38 while not forming any areas in the primary combustion chamber 30 that would quench the fire in the primary combustion chamber 30 in any manner. The inner wall 18 of the water jacket 20 thermally conducts heat from the heated air in the air chamber 40 and the water within the water jacket 20 thermally conducts the heat from the inner wall 18 of the water jacket 20. The outer wall 17 of the water jacket 20 preferably does not exceed a temperature of 190 degrees Fahrenheit. The heated water is exhausted through the water outlet 29 to be used for heating air in a furnace, electrical power generation or other suitable purpose. Cooled water enters the water cavity 19 of the water jacket 20 via the water inlet 21 to be heated and then dispensed through the water outlet 29. The heated gases from the primary combustion chamber 30 then pass through the connecting tube 60 and are further burned in the second combustion chamber 70 to remove pollutants and other materials from the heated gases prior to dispensing through the exhaust port 74. If the primary combustion chamber 30 should become damaged requiring replacement or repair, the user simply removes the front end plate 23 of the water jacket 20 and removes the primary combustion chamber 30 through the front opening 24 for repair and/or replacement.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar to or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described above. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety to the extent allowed by applicable law and regulations. The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore desired that the present embodiment be considered in all respects as illustrative and not restrictive. Any headings utilized within the description are for convenience only and have no legal or limiting effect. 

The invention claimed is:
 1. A biomass boiler system, comprising: a primary combustion chamber having an exterior surface and an interior surface, wherein said interior surface defines a combustion chamber for combusting biomass material; and a water jacket having an inner wall, an outer wall and a water cavity defined between said inner wall and said outer wall, wherein a substantial portion of said inner wall is distally spaced a distance from said exterior surface of said primary combustion chamber forming an air chamber, and wherein said water cavity contains a volume of liquid heated by thermal conduction of heat from said primary combustion chamber through said air chamber then through said inner wall of said water jacket.
 2. The biomass boiler system of claim 1, wherein said primary combustion chamber does not have a ceramic coating.
 3. The biomass boiler system of claim 1, wherein said primary combustion chamber does not have an insulation layer.
 4. The biomass boiler system of claim 1, wherein said liquid is comprised of water.
 5. The biomass boiler system of claim 1, wherein said inner wall is not directly connected to said primary combustion chamber.
 6. The biomass boiler system of claim 1, wherein said distance between said inner wall and said exterior surface of said primary combustion chamber is approximately one inch.
 7. The biomass boiler system of claim 1, wherein said distance between said inner wall and said exterior surface of said primary combustion chamber is at least one inch.
 8. The biomass boiler system of claim 1, wherein said air chamber surrounds a substantial portion of said primary combustion chamber.
 9. The biomass boiler system of claim 1, wherein said primary combustion chamber is comprised of a main wall forming said exterior surface and said interior surface, a front wall connected to said main wall and a second wall connected to said main wall opposite of said front wall.
 10. The biomass boiler system of claim 9, wherein said air chamber completely surrounds said main wall.
 11. The biomass boiler system of claim 10, wherein said air chamber surrounds a substantial portion of either said front wall or said rear wall.
 12. The biomass boiler system of claim 9, wherein said primary combustion chamber includes a plurality of air inlet ports within a lower portion of said main wall, wherein said plurality of air inlet ports draw in heated air from said air chamber into said primary combustion chamber.
 13. The biomass boiler system of claim 9, wherein said primary combustion chamber is comprised of a cylinder.
 14. The biomass boiler system of claim 13, wherein said water jacket is comprised of a cylinder.
 15. The biomass boiler system of claim 1, including a door for selectively opening and closing an opening that extends through said water jacket and said primary combustion chamber.
 16. A biomass boiler system, comprising: a primary combustion chamber having an exterior surface and an interior surface, wherein said interior surface defines a combustion chamber for combusting biomass material; a water jacket having an inner wall, an outer wall and a water cavity defined between said inner wall and said outer wall, wherein a substantial portion of said inner wall is distally spaced a distance from said exterior surface of said primary combustion chamber forming an air chamber, wherein said water cavity contains a volume of liquid heated by thermal conduction of heat from said primary combustion chamber through said air chamber then through said inner wall of said water jacket, and wherein said liquid is comprised of water; wherein said air chamber surrounds a substantial portion of said primary combustion chamber; wherein said primary combustion chamber is comprised of a main wall forming said exterior surface and said interior surface, a front wall connected to said main wall and a second wall connected to said main wall opposite of said front wall; wherein said air chamber completely surrounds said main wall; wherein said inner wall is not directly connected to said primary combustion chamber; wherein said distance between said inner wall and said exterior surface of said primary combustion chamber is at least one inch; and a secondary combustion chamber fluidly connected to said primary combustion chamber.
 17. The biomass boiler system of claim 16, including a connecting tube fluidly connected between said primary combustion chamber and said secondary combustion chamber.
 18. The biomass boiler system of claim 17, including a catalytic unit connected to said connecting tube.
 19. The biomass boiler system of claim 16, wherein said primary combustion chamber does not have a ceramic coating.
 20. The biomass boiler system of claim 16, wherein said primary combustion chamber does not have an insulation layer. 